[1] Cambridge Univ Hosp, Addenbrookes Hosp, NHS Fdn Trust, Clin Gerontol Unit, Cambridge CB2 0QQ, England
[2] Addenbrookes Hosp, Dept Clin Neurosci, Lewin Stroke & Rehabil Unit, Cambridge, England
[3] Addenbrookes Hosp, Dept Rheumatol, Cambridge, England
[4] Univ E Anglia, Sch Med, Norwich NR4 7TJ, Norfolk, England